"staff dont want to work sundays". So if that's true, why do they think they are so special? It's the only line in the country closed all day Sunday.
Closing on Saturday instead would not be a solution as there is probably quite an amount of leisure/shopping traffic on Saturdays: it's not like Dublin-Cork in that the midweek business traffic is probably very minor.
A more general problem is that there are 13 manned level crossing between L Jcn and Waterford: a huge number by contemporary standards.